I found this forum looking for some dish 4 valve relief piston volume numbers, which I found - sort of. I'm hoping they are 12-13cc.

I'm trying to figure out if I should...

1/ put some ported 58cc 305 heads with 1.94/1.6 valves and a stock gasket or
2/ get some 64cc promaxx 183's (maybe cut to 62) with thinner head gaskets to help keep the compression at 9.5:1 approximately regardless of the heads.

The engine it's going on is a 350 at 040 over with stock replacement pistons (cast dish 4 valve relief), recently rebuilt.

The 305 heads are a little cheaper, which helps me maintain my budget street engine goal, but the promaxx aluminum heads flow really well.

I really have no idea how well the 305 heads will perform compared to those new aluminum heads, which is what i hope I can get a feel for.

The cam it most likely going to be a comp magnum 270H, since it's part of the budget program i'm on and it's available. I also have an edelbrock 7501 ready to go on it and still deciding on a carb.

Does anyone have any experience on how well those ported 305 heads will work in comparison to those aluminum ones? Pros? Cons?